% bin/hadoop-ec2 launch-cluster my-hadoop-cluster 10

When the master has started the console will display a message like

Master is ec2-xxx-xxx-xxx-xxx.compute-1.amazonaws.com

To access Hadoop's web UI you need to allow access to the relevant ports by setting permissions on the security groups in your cluster. This is most easily achieved using Elastic Fox, a Firefox plugin for managing EC2 instances. In the Elastic Fox control panel:

	Tip
	To monitor MapReduce jobs visit http://ec2-xxx-xxx-xxx-xxx.compute-1.amazonaws.com:50030 in a browser (substituting the hostname printed when the master started). Similarly, you can monitor HDFS at http://ec2-xxx-xxx-xxx-xxx.compute-1.amazonaws.com:50070.

	Note
	If you have selected an instance with multiple disks (one of the large or xlarge instances) then it will take several minutes for the cluster to come up after the instance has started, since the extra disks need to be formatted first.

% bin/hadoop-ec2 login my-hadoop-cluster

This opens an SSH session to the master node which is a convenient place to run jobs from. For example, let's create some test input to run a job on:

# hadoop fs -mkdir input
# hadoop fs -put /etc/hadoop/conf/*.xml input
# hadoop jar /usr/lib/hadoop/hadoop-*-examples.jar grep input output 'dfs[a-z.]+'
# hadoop fs -cat output/part-00000 | head

	Caution
	WHEN YOU TERMINATE YOUR CLUSTER ALL DATA WILL BE LOST!

% bin/hadoop-ec2 terminate-cluster my-hadoop-cluster